Bioremediation of oil-contaminated soil in Kuwait

This paper summarizes the results of a 1-ha large-scale bioremediation field experiment of oil-contaminated soil in Kuwait's desert. Three techniques were used: landfarming, windrow composting soil piles and static piles fitted with an enforced aeration system. Total petroleum hydrocarbon (TPH) values decreased rapidly during the first 4 mo and then more gradually over the subsequent months. After 15 mo, 75 to 80% of the TPH in all the plots and piles had been degraded. More than 80% of3-ring PAHs and 50% of 4 ti, 5-ring PAHs were degraded after 12 mo of treatment. Of the three methods tested, the landfarming method achieved in the highest decomposition rate and resulted in the greatest reduction in bioremediation time. Plant toxicity experiments were carried out using 15 mo bioremediated soil. The yield was almost within the normal range, so the treated soil had been sufficiently restored for vegetation. From the plant analysis after vegetation, it was clear that the uptake of PAH, sulfur and heavy metals were negligibly small. This study was carried out under the Joint Research Program between the Petroleum Energy Center under the Ministry of International Trading and Industry, Japan, and the Kuwait Institute for Scientific Research, Kuwait.